Apparatus and method for reprocessing lumened instruments

ABSTRACT

Apparatus and methods for processing an item, such as a lumened instrument, secured in a connectorless fashion in a push/pull reprocessor. The push/pull reprocessor includes a container having a first chamber and a second chamber and a pressure sensor in each chamber such that the method includes the step of generating a flow of a liquid, such as ozonated water, back-and-forth upon the item or additionally through a lumen in the case of a lumened instrument.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. patent applicationSer. No. 14/152,789, filed on Jan. 10, 2014, which is a continuation ofU.S. patent application Ser. No. 12/247,830, filed on Oct. 8, 2008,which is a continuation-in-part of U.S. patent application Ser. No.11/367,787, filed Mar. 3, 2006, the contents of which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates generally to improved apparatus and methods forreprocessing items including items with lumens, and, more particularly,to apparatus and methods that involve flowing a liquid between chambersin a divided container containing the item to be processed for cleaning,sterilizing, pre-treating, rinsing or the like.

2. Description of the Related Art

The reprocessing (i.e., cleaning and decontamination) of items that comeinto contact with the bodily substances of people or animals such thatthey are substantially “substance free” (of, e.g., viruses, bacteria,detergent, sterilant, lipids, etc.) represent an immense and ongoingchallenge. This challenge has been underscored by a recent articleentitled “Widely used sterilizer under attack” (published in Jan. 21,2003 edition of the newspaper USA Today). The article describes a fataloutbreak of bacterial infection that was linked to the impropersterilization of hospital bronchoscopes. Despite the hospital's use ofone of the most popular sterilizing systems, tests performed by theCenters for Disease Control and Prevention found bacteria on thesystem's water filters and in its rinse water. This and other infectionoutbreaks have led to continuing controversy over how best to clean andsterilize used endoscopes. These challenges persist to the present day.

The contaminants typically found on items such as tubular or “lumened”medical items, e.g. endoscopes, are especially difficult to remove. Inaddition to fecal mater, loose cellular debris, blood and bloodproducts, viruses, and bacteria, an endoscope can be coated with varioushydrophobic films, such as “biofilm” material. A biofilm typicallycomprises cells, both dead and alive, cell debris and extracellularpolymer substances. Once biofilm is formed by microorganisms (includingbacteria, fungi, and protozoans), these microorganisms can colonize andreplicate on the interior surfaces of tubing, forming a protective slimelayer known as a “glycocalyx” that is especially difficult to remove.

Merely soaking endoscopes in a sterilant or detergent is unacceptablesince numerous pockets exist within the tubing where the sterilant ordetergent cannot reach effectively, which leaves areas of contaminationwithin the endoscope. Moreover, with the prevalence of highly contagiousdiseases such as hepatitis B and C and Acquired Immune DeficiencySyndrome, as well as the pathogens MRSA (Methicillin-resistantStaphylococcus aureus) and Clostridium difficile, reliable sterilizationor disposal of all used medical tools seemingly becomes mandatory. Yet,while many medical instruments today are routinely cleaned, disinfected,and reused, experts in the field recently have warned that some of themore difficult to clean and sterilize medical items are putting peopleat risk. For example, the website “myendosite.com” contains scores ofrecent references involving infection and endoscopy in the news (seemyendosite.com/infection_control_media.htm).

Many attempts to improve sterilization apparatus and methods have beentried over the years. For example, a variety of gas sterilizationmethods has been investigated in the past. Methods using ethylene oxideand other disinfecting gases are widely used for sterilizing a widerange of items, from contact lenses to surgical instruments.

A sterilizing method must effectively kill all organisms, includingspores, without damage to the article or goods being sterilized.Moreover, before sterilization can take place, the instrument must becleaned to the FDA quantifiable validated standard of clean. Indeed, noreprocessor on the market can perform this other than the unique“push/pull reprocessors” created by the inventor and described below.

So-called “push/pull reprocessing systems” are automatic apparatusesthat include a chamber containing a baffle with one or more openingsthrough which water (or another fluid) surges in a synchronous fashionback-and-forth (hence “push/pull”) through the opening or openings inthe baffle. When soiled items, such as endoscopes and other lumenedinstruments, are placed within an opening in the baffle, fluid alsosurges upon and through them. Accordingly, a back-and-forth “scrubbingaction” is created by the surging fluid the contacts any accessiblesurface on an item, including any lumen or lumens.

For example, U.S. Pat. No. 5,711,921 by Langford discloses a medicalapparatus cleaning mechanism that includes a container having a firstchamber and a second chamber, with the container adapted to accept amedical instrument such that a first portion of the medical instrumentlies in the first chamber and a second portion of the medical instrumentlies in the second chamber. Pumping means then simultaneously increasefluid pressure within the first chamber of the container whiledecreasing fluid pressure within the second chamber until the cycle isreversed, i.e., the fluid pressure in the second chamber increases whilethe fluid pressure in the first chamber synchronously is decreased.

While the Langford apparatus is known to provide superb cleaning andsterilization, the teachings of the Langford patent appear limited tothe use of the apparatus with a single-size lumen diameter and do notspecify how to evacuate the entire lumen volume per each change in fluidflow direction (i.e., a “stroke”).

U.S. Pat. No. 6,534,002 by Lin further notes alleged shortcomings of theteachings in Langford as follows: “One significant problem with thissurging mechanism for cleaning endoscopes results from the fact thatendoscope channels often have different diameters at their oppositeends. As fluid flows from the larger-caliber end of an endoscope channelto the smaller-caliber end, particulate matter and human tissue,secretions, and excrement can become lodged in the smaller-caliber endand extremely difficult to extract. Another problem with the surgingmechanism results from the frequent change in directional flow of fluidthrough the channels of an endoscope. In cleaning an endoscope, debrismust travel a long distance, sometimes more than 150 cm, to traverse thelength of the endoscope before the debris can exit the endoscope. Insurging methods of cleaning endoscopes, some fluid, debris, and airpockets may move back and forth within the endoscope channel, but nevertravel far enough to exit the channel before the next directional shiftin flow occurs. Thus, some debris and air pockets can remain trapped inthe central portion of an endoscope channel with the surging method ofcleaning.”

The main thrust of how the Lin patent proposes to deal with theseshortcomings involves generating a flow of sanitizing solution through alumened instrument in predominantly one direction, from thesmaller-caliber end to the larger-caliber end, to clean or sterilize theinner surface of the device.

However, flowing a fluid in “predominantly one direction” does notnecessarily result in better cleaning or sterilizing action; indeed,material may become trapped in complex lumened instruments (such as arestrictor valve in a colonoscope or the spring and guide wire of abiopsy forceps) if a recurring back-and-forth motion is not used todislodge it.

From the above, it can readily be seen that complex lumened medicaldevices present unique challenges. Some instruments (e.g., abronchoscope) have a main lumen of one diameter and another lumen ofsmaller diameter branching off the main lumen, presenting two resistanceratings inside the same instrument. Furthermore, various lumenedinstruments have restrictor valves inside the lumen narrowing the fluidpath in one direction. This acts as a point of blockage or increasedresistance if debris is pushed up against the restrictor. Thus, forthose devices that have different size internal lumens in the sameinstrument, as well as for those that can be 6 feet or longer in length(e.g., a colonoscope), resistance to fluid flow during cleaning andsterilization presents a difficult problem.

Accordingly, it would be desirable to provide an apparatus and methodsthat carry out effective cleaning and sterilization of even complexlumened instruments quickly and thoroughly, while reducing undesirableeffects. In addition, it is desirous that the fluid flow about theexterior of a lumened instrument cause sufficient turbulence to cleanthe outside of the instrument as well.

SUMMARY OF THE INVENTION

The invention generally involves methods and apparatus for reprocessingitems, such as medical or dental items. According to one aspect of theinvention, a lumened instrument reprocessing apparatus is provided. Theapparatus includes two chambers and a holder to connectorlessly secure alumened instrument such that a first portion of the lumened instrumentlies in the first chamber and a second portion of the instrument lies inthe second chamber, a liquid medium contained within the two chambers,and pumping means for simultaneously increasing fluid pressure withinthe first chamber of the container while decreasing fluid pressurewithin the second chamber of said container in a reciprocating fashion.The pumping means is designed to displace at a substantially constantpressure at least a total internal volume of the liquid medium throughthe lumen for a given highest volume of a lumened instrument during eachstroke.

In another embodiment, an item is cleaned within a push/pullreprocessing apparatus, contained within sterilizable packaging, andsterilized within the reprocessing apparatus through the introduction ofa sterilant, the flow of which includes fresh or new sterilant, such assteam, at one or more times during the sterilizing cycle. Thus, a devicecan be removed from the apparatus in a sterile package, therebymaintaining post-processing sterility.

In still another embodiment, the invention includes methods ofprocessing an item secured in a connectorless fashion in a push/pullreprocessor, with the push/pull reprocessor including a container havinga first chamber and a second chamber and a pressure sensor in eachchamber. The methods include the step of generating a flow of a fluidbetween the first and second chambers and contacting the instrument.

A removable baffle plug of the invention is provided to allow for theplacement of different sized items within the baffle, to modulate thepressure between parts of the chamber on either side of the baffle, andto provide information about what is being placed in the chamber throughthe use of radio frequency identification devices. The plug allows flowbetween the device being held and the interface, thereby creating aturbulent flow to clean the device exterior in each direction.

In another embodiment, the pressure within both chambers of thepush-pull apparatus is kept substantially constant. For example, thepumping means is used to keep the pressure around 12.5 psi in someembodiments of the invention.

In accordance with the above methods, there is provided new and improvedapparatus for sterilizing an item.

Various other purposes and advantages of the invention will become clearfrom its description in the specification that follows. Therefore, tothe accomplishment of the objectives described above, this inventionincludes the features hereinafter fully described in the detaileddescription of the preferred embodiments, and particularly pointed outin the claims. However, such description discloses only some of thevarious ways in which the invention may be practiced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts in a cross-sectional view a “push-pull” reprocessingapparatus of the prior art.

FIG. 2 schematically illustrates a first apparatus and method embodimentof the invention.

FIG. 3 schematically illustrates a second apparatus and methodembodiment of the invention.

FIG. 4 schematically illustrates a third apparatus and method embodimentof the invention.

FIG. 5 schematically illustrates an enlarged view of section X takenfrom FIG. 4.

FIG. 6 schematically illustrates the same enlarged view as FIG. 5 butwith the packaging around the item closed.

FIG. 7 shows a removable baffle plug of the invention.

FIG. 8 schematically illustrates another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The terms “push/pull apparatus,” “push/pull system,”“cleaner/sterilizer,” “push/pull reprocessor,” “reprocessor,” and“reprocessing” as used throughout the specification are meant to besynonymous with the use of a push-pull apparatus (such as the LangfordIC Systems, Inc. Manzi Mach 1) that cleans items (e.g., endoscopes,dental appliances, surgical instruments and the like) by surging fluidback-and-forth upon the accessible surfaces of these items.

The term “bi-directional” means flowing in two directions at once withinthe container of the invention.

As used herein, the term “plasma” is intended to include any portion ofthe gas or vapors which contains electrons, ions, free radicals, and thelike produced as a result of an applied electrical field, including anyaccompanying radiation that might be produced. While radiation in theradio frequency range is most commonly applied, a broad frequency rangemay be used.

Turning to the figures, wherein like numbers designate like features,FIG. 1 depicts a “push-pull” reprocessor of the prior art. An item witha lumen 2 is secured within an opening of a baffle 4 that divides thereprocessor into a first chamber 6 and a second chamber 8. When valves12 and 14 are opened and diaphragms 10A and 10B are simultaneouslyactivated in opposite directions as shown, fluid F flow through andaround the lumen 2. By reversing the direction of the diaphragms 10A and10B in unison, a linear or unidirectional flow is created first one wayand then the other, resulting in a periodic shear force or “scrubbingaction.”

FIG. 2 illustrates in simple schematic form a first embodiment of theinvention. Unlike the linear flow of an initial quantity of “old”sterilant and “push/pull” action created by the apparatus of FIG. 1,this embodiment of the invention bi-directionally flows fresh sterilantinto chamber 18. Thus, for example, mixing tank 16 housing gas plasma isdistributed into chamber 18 via a pump 20 and a bi-directional valve 22.The bi-directional valve 22 conveys plasma into first chamber 24 andsecond chamber 26 at the same time, resulting in a bi-directional flow(indicated by arrows 28A and 28B for inflow and arrows 30A and 30B foroutflow when the pump is reversed) over item 32 and gas permeablepackaging 34. Reversing the pump at desired intervals (e.g., 2 secondsas shown) allows for at least partial evacuation of “old” sterilantwhile introducing fresh or “new” sterilant upon the item 32.

While a chamber 18 containing a baffle 36 is shown in this and otherembodiments, it should be understood that the invention may include achamber with no baffle and into which an item is simply placed orsecured to a clamp or other structure within the chamber. Moreover, theinvention is not limited to gas plasma. Other sterilants may include,for example, ethylene oxide or steam.

In view of the above apparatus and explanation, a method for sterilizingan item encompasses: placing an item 32 within an opening in baffle 36such that the item 32 extends into the first chamber 24 and secondchamber 26, introducing the sterilant into the first and second chamberssuch that the sterilant is made to flow bi-directionally (28A, 28B, 30A,30B) in the chambers, and sterilizing the item while introducing freshsterilant (symbolized by arrows A and B) into the chamber 18 at leastonce during a sterilizing cycle.

The methods of the invention are especially suitable for sterilizationof an item inside a gas-permeable sleeve or packaging 34, because thelack of linear flow or substantial “back and forth” motion reduce thechances that the packaging will be damaged or lost (through, forexample, being impaled by the item 32 or by sliding off as a result ofbeing pulled in one direction). In the embodiment shown in FIG. 2, thisis accomplished by introducing and evacuating the sterilant on each sideof said baffle to provide a continuous bi-directional flow upon item 32.

In another embodiment of the invention pictured in FIG. 3, gas plasmafrom tank 16 is alternately introduced on each side of baffle 36 throughreversing the one-way pump 40 (during periods in which valve 41 isopen). Because sterilant is introduced into only one of chambers 24 or26 at a time, this embodiment initially appears to provide a“uni-directional” flow of fresh sterilant suitable for sterilizing anitem with a lumen. However, as the one-way pump is reversedperiodically, the net effect is have gas flowing within the apparatus 18dynamically to both chambers, with new sterilant being introduced asdesired by opening valve 41.

FIG. 4 illustrates a third embodiment of the invention. Here, thebi-directional flow of sterilant from mixing tank 16 is created by aplurality of pumps 46 and 48. Similar to the one-way pump show in FIG.3, a net bi-directional flow effect is created by alternating betweenpump 46 and 48. Moreover, pumps 46 and 48 can be used at the same timeto create a “pulsing” effect, whereby waves of fresh sterilant areintroduced into chamber 18. The pumps may provide a continuous flow offresh sterilant or may pump the existing sterilant (though the use ofvalves or a bypass (not shown) with the mixing tank 16), with newsterilant being introduced as desired.

In some applications, it may be preferred to dry an item prior tointroducing a sterilant. Thus, drying means 47 is connected to chamber18 to provide heated air. Alternatively, alcohol (e.g., 70% ethanol) ora vacuum can be provided in order to dry item 32.

FIGS. 5 and 6 are greatly enlarged views of section X of FIG. 4. Thus,opening 38 in baffle 36 is more clearly seen. Preferably, the item 32 iscontained in a bag 34 having a sealable end 39 (e.g., such as byadhesive) and is placed into opening 38. Also preferably, the item 32and opening 38 have a “wet fit,” meaning that the friction between theopening and the item is such that fluid (including a gas) can flowbetween different sides of the baffle 36 as shown by arrow AC.

To control the flow between different sides of baffle, and to make thebaffle adaptable to different sized items, one or more removable plugsmay be used with the invention. Turning to FIG. 7, baffle 50 has aremovable plug 52 that is disposed within notch 60 and in sealedarrangement therewith. Thus, plugs with different sized openings 62 maybe utilized for different sized items. Moreover, one or more plugs 52may be removed or filled in to change the flow dynamics between chamberson either side of the baffle.

Also, radio frequency (RF) transmitters and receivers can be used inconjunction with the plug of the invention. Thus, RF device 70 disposedupon plug 52 can be used to identify a compatible item also containing aRF device. For example, RF device 70 could identify a bronchoscopeplaced within the opening 62 of plug 52 and transmit such information tothe operator of the sterilizing apparatus so that a particular programor cycle could be employed.

The pressure present within a push-pull apparatus during reprocessingoperations should be kept substantially constant to avoid collapsing thelumen passage. Moreover, constant pressure during each stroke bestensures that a given flush volume will travel through each lumenedinstrument every time (i.e., the lumen flush volumes are maximized andconsistent for each stroke). However, in view of the variations andcomplexity of lumened instruments, it can be problematic to thoroughlyclean and sterilize them through evacuation of the lumen in bothdirections at a consistent pressure.

Previous reprocessor apparatus, such as the FDA cleared Manzi Mach 1Cleaner Processor System, use a basic control scheme to generate theprocess pressures that result in fluid flow through instrument lumens.This control scheme employs a reciprocating pump operating at a constantspeed. The constant speed control scheme operates the pump at a constantspeed independent of the resulting pressure. Thus, the resultingpressure produced is a product of (i) the volume of fluid (ratio ofchamber fluid to chamber air) and (ii) the baffle restriction thatdivides the chamber into two halves. Since the volume of fluid deliveredinto the chamber can be different from one cycle to the next (this isdue, in part, to the available municipal water pressure supplied and theprecision of the sensors detecting fluid level), different operatingpressures can result.

This range in chamber operating pressures causes the following: Largechamber structure to account for high pressure, reduced fluid flowthrough instrument lumen at low pressure, increased fluid flow throughinstrument lumen at high pressure, and reduced margin on instrumentpressure rating. This constant speed control scheme also produces largetransient pressures and transient pressure drop-outs which occur due tothe fluid dynamics. In other words, there is no active control of theoperating pressure.

Thus, the invention relates to controlling the pressure and amount offluid that is moved from one side of a divided chamber to the other suchthat the fluid is in excess of the total internal volume of the lumenedinstrument(s) being processed. In other words, at least one entirevolume is passed through the lumened instrument(s) being processed forevery directional change in fluid flow or “stroke” of a push-pullinstrument reprocessor. Moreover, each stroke preferably is performed ata constant pressure. Preferably, the total internal volume of a lumenedinstrument is exceeded by at least 1% to better ensure that any effectson flow dynamics caused by changes in diameter or the presence of otherstructures inside the lumen are accounted for.

Thus, the inventor has developed an improvement to the above scheme byactively controlling the operating chamber pressure, thereby producingmore consistent flow through instrument lumens and further reducing thepossibility of instrument damage. The active pressure control schemeimplemented is known as a PID controller (proportional, integral,derivative controller) and can be implemented in hardware or software ora combination. In one embodiment, this improvement is implemented insoftware.

The PID software design relies upon acquiring (reading) pressure valuesfrom two pressure sensors within the reprocessor container and adjustingthe pump rate (speed) so as to cause the pressure to remain within adefined range (target range). The PID controller implements thefollowing:

-   Proportional (error)=present behavior-   P=(requested pressure−actual pressure)/Requested pressure-   Integral=past behavior-   I=(previous I)+P-   Derivative=future behavior-   D=P−(previous P)-   A scaling value is calculated: S=pScale*P+iScale*I+dScale*D

Variable Coefficient Startup Values pScale 0.06 iScale 0.02 dScale −0.02Operational Values pScale 0.04 iScale 0.02 dScale −0.03

-   The motor speed is adjusted: Target speed=Target speed+S*Target    speed

The result of the pressure control algorithm above is that sufficientfluid flow is generated at a controlled (constant or substantiallyconstant) pressure to clean the inside of complex lumened devices ofpractically any length, even with restrictor valves in place or guidewires and other similar obstacles to normal fluid flow. Also, bycompletely evacuating the entire lumen(s) volume every stroke,consistent turbulence is created to clean the outside of the instrumentsand any other non-lumened instruments placed in the same chamber.

Turning to the simplified schematic diagram shown in FIG. 8, areprocessing apparatus 70 is shown that includes a container 72 having afirst chamber 74 and a second chamber 76 that are divided from eachother by a holder 78 to connectorlessly secure a multi-branched lumenedinstrument 80. Ideally, a first portion of the lumened instrument 80lies in the first chamber 74 and a second portion lies in the secondchamber 76.

A liquid medium 82 is contained within both chambers of the containerand is surged back-and-forth by a pumping means 84 that generate astroke by simultaneously increasing fluid pressure within the firstchamber of while decreasing fluid pressure within the second chamber.The pumping means 84 is controlled to displace at least a total internalvolume (V) of the liquid medium 82 through the lumen 86 of instrument 80during each stroke (even when different diameters are present within theinstrument, such as that caused by restrictor valve 88). Thus, forexample, a signal is sent to open valves 88 and 90, whereupon pumpingmeans 84 acts upon diaphragms 92 and 94 to generate a stroke (symbolizedby arrows S) of fluid flow.

The pumping means 84 is controlled to generate a substantially constantpressure P within both chambers of the container 72. Preferably,constant pressure of between 1-29 psi is achieved. Pressure ismaintained according to pressure sensors 96 and 98, which readings fromeach chamber 74, 76 inform the pumping means to vary its motor speed asneeded to ensure that the pressure within each chamber remainssubstantially constant.

The instrument 80 preferably has a “wet fit” within the holder 78 thatallows flow between the device being held and an opening of the holder,thereby creating a turbulent flow 100 to clean the instrument exterior.

The inventor has found that not filling the container 72 to the top withfluid 82 results in better cleaning dynamics, particularly of instrumentexteriors. Thus, preferably the container 72 includes a volume of air102 of between 1-25% at the container top (e.g., 95% fluid, 5% air). Theinventor has tried air volumes of up to 25% with good results.

In view of the apparatus shown in FIG. 8, a method for processing (e.g.,cleaning and/or sterilizing) an item is provided. In some cases, an itemhas a lumen. A reprocessor having a back-and-forth motion and includinga container having at least one interface that separates the containerinto two or more chambers or compartments is utilized, with each chamberor compartment having a pressure sensor as disclosed in FIG. 8, forexample. An item such as a medical or dental instrument is engaged in aconnectorless fashion (i.e., its ends are not coupled with a fittingthat shoots fluid upon the instrument and/or within the instrument lumenif one is present) within an opening in the interface. Then, a flow of afluid from inside the container is generated such that it movesback-and-forth between the two chambers. Preferably, the flow exceedsthe total internal volume of a given lumen (if one is present) by atleast 1% to ensure full flow-through of even very complex lumenedinstruments. Also preferably, the back-and-forth flow of fluid occurs ata substantially constant pressure. Ozonated liquid has been found toperform exceptionally well with this method as further described below.

Within the following examples, endoscopes or other medical or dentalinstruments will be used as an example of an item or instrument to bereprocessed. However, the inventor contemplates use of the inventionwith any tubular item, as well as a variety of other items such ascircuit boards, cosmetic instruments, food preparation instruments, andother items in which reliable cleaning and sterility are desirable orrequired.

EXAMPLE 1

This example utilizes the apparatus shown in FIG. 8. After securing alumened instrument with baffle fittings designed for different sizelumened instruments with one opening of the lumened instrument in oneside of the divided container and the other in the other side of thecontainer. Both chambers of the container are filled to 95% of totalcontainer volume with filtered water containing an effective amount of acleaning agent. The reprocessing apparatus is activated and one side isbrought to a positive pressure and the other to a negative pressure andreversed for 10 minutes by the pumping means. During each stroke of thereprocessor, a pressure sensor in each chamber of the divided containermonitors the pressure and provides feedback used by a controller toadjust the speed of the pumping means such that a substantially constantpressure is maintained at 12.5 psi.

EXAMPLE 2

The purpose of this test is to document the results of engineeringcharacterization testing performed on a automatic endoscope reprocessor,the Langford I.C. Systems Sterilizer Cleaner (see U.S. Pat. No.5,906,802 for layout and guidance in the use of this reprocessor).Testing was performed on a Cleaner, Sterilizer Breadboard.

The biopsy lumen of three bronchoscopes were loaded with Birmingham Soil(much more than required by FDA test standards) and inoculated withpathogens from an American Society of Test Methods kit. The scopes wereleft sitting for a 24 hour time period to permit some drying. Using thesame Langford I.C. Systems Sterilizer Cleaner liquid-displacementsettings as described, each bronchoscope was subjected to one wash cycleat 10 psi for 5 min with a use concentration of 2.5% of enzymaticcleaner in 10 liters of water. The preferred rate of “liquiddisplacement” (i.e., the back-and-forth liquid cycling rate in theitem-washing chamber of the Sterilizer Cleaner) is 1 gallon per 2seconds.

Upon completion of the cleaning cycle, and if gas plasma use is desired,the bronchoscope is dried for 5 minutes with heated air and thesterilization cycle could take place by flowing gas plasma for 5-30minutes upon the bronchoscope. At least once after the beginning of thesterilizing cycle, fresh gas plasma is pulsed into the chamber to betterensure all surfaces are contacted with active sterilant.

EXAMPLE 3

A surgical item is placed in a multi-chamber reprocessor and cleaned asabove. The item is then packaged and sealed in a cellulose envelope andtransferred to a chamber separate from the cleaning chamber. Theseparate chamber includes a fluid port to bi-directionally inject gasinto the chamber, with a pump alternately applying positive pressure tothe chamber and a vacuum to evacuate the chamber. The separate chamberincludes radio frequency electrodes to generate the requisite radiofrequency signal. The plasma is generated by evacuating the chamber,introducing a gas or vaporized liquid and turning on the power to theelectrodes. The plasma is generated in the present process in the samemanner as in known prior art plasma sterilization system (e.g., U.S.Pat. No. 4,643,876). The surgical item is exposed from 5-30 minutes tothe plasma.

By way of example, hydrogen peroxide is injected in the form of anaqueous solution of hydrogen peroxide containing from about 3% to 20% byweight of hydrogen peroxide. The concentration of hydrogen peroxidevapor in the chamber may range from 0.05 to 10 mg of hydrogen peroxideper liter of chamber volume. A concentration of 0.125 mg per liter isthe minimum preferred concentration of hydrogen peroxide. Air or aninert gas such as argon, helium, nitrogen, neon or xenon may be added tothe chamber with the hydrogen peroxide to maintain the pressure in thechamber at the desired level. The hydrogen peroxide solution may beinjected in one or more separate injections. Since the hydrogen peroxideis decomposed into non-toxic products during the plasma treatment, noadditional steps are required to remove residual hydrogen peroxide fromthe sterilized object or its packaging prior to use of the object.

Alternatively, if sterilization of a lumened instrument (e.g., abronchoscope) is desired, the above method could be modified for use ina push/pull reprocessor to flow gas plasma upon all accessible surfaces,including the exterior and through the lumen of the scope (before orafter any packaging of the item takes place). “Unidirectional” flow(with occasional reversal of direction) would be employed to urge thegas plasma (or other vapor-phase sterilants, such as steam) toeffectively permeate through the entire lumen.

EXAMPLE 4

To prove disinfection to the FDA requires the disinfecting medium tokill mycobacterium terrae for high level disinfection and bacillussubtilis to prove sterilization. By soaking in an ordinary aqueoussolution of ozonated liquid such as water, the required contact time isapproximately 40 minutes to kill bacillus subtilis at a concentrationthat will cause the least amount of corrosion. For example, a 90%reduction of B. subtilis is achieved at 0.10-PPM of ozone for 33minutes. However, it has been found that if this same concentration ofozone is used in conjunction with the disclosed push/pull device, thecontact time is less than 5 minutes because the ozone is delivered toall the surfaces continuously.

This synergistic effect occurs even when the instrument consists ofnarrow lumens and even more so when the lumens are longer than 24inches. The ozone is delivered already in solution to the chambers andthe surge action delivers the ozone to all surfaces of any instrumentboth inside and outside to maximize contact time and at lowerconcentrations than required if the instrument were to be merely soakedin an ozone solution. Moreover, the generating step of the method can beperformed at a pressure or speed such that an amount of time required tokill a given pathogen is lessened for a given concentration of ozone inthe ozonated liquid.

Preferably, fresh ozone is continuously introduced into the ozonatedliquid such that a contaminant in or on an item in the reprocessor iscontinuously exposed to fresh ozone. The ozone may be supplied fromsystems know in the art, such as by systems including an oxygengenerator, ozone generator and water chiller. The chambers arecontinuously fed with ozonated water and replenished or boosted withozone injected directly into the chamber using, for example, either aventuri feed in an aqueous solution or ozone through a diffuser.

A benefit of using a connecter less push/pull system with a controlledpressure differential between the separated chambers is to ensurecontact with all surfaces and maximum contact in lumened instrumentscontaining restrictor valves and/or differing diameters and length. Thelessening of the contact time in the reprocessor cuts down dramaticallyon the corrosive effects of ozone on surgical and diagnostic instrumentsversus the long contact time needed to achieve the same results if theinstruments are soaked in an ozone solution. Because ozone has a lifespan of 33 minutes on average and the soaking time would exceed it inorder to kill bacillus subtilis and the only manner in which this couldbe mitigated is to increase the concentration of ozone thereby damagingor destroying the instrument.

Using ozone in an aqueous solution is synergistic to the push pullsystem controlled by pressure sensors to maintain a pressuredifferential, e.g. of 1 psi between the chambers, in that itseffectiveness lessens the concentration of ozone and/or contact timerequired to disinfect the instruments versus soaking them in an aqueousozone solution thereby mitigating the corrosive properties of ozone athigh concentrations over a longer contact time.

By way of further example, a method of preventing or reducing biofilm inan empty push/pull reprocessor having a pressure sensor in each chamberalso is contemplated. The reprocessor generates a flow of a sanitizingliquid, such as ozonated liquid, between the first and second chambers.Preferably, ozone is continuously added to the liquid such that thesurfaces of the chambers, the baffle, and all other areas in contactwith the liquid are exposed to the ozone. Moreover, because of thesurging action controlled by the pressure sensors, any existing biofilmis reduced by the “sheering action” of the liquid.

Various changes in the details and components that have been describedmay be made by those skilled in the art within the principles and scopeof the invention herein described in the specification and defined inthe appended claims. Therefore, while the present invention has beenshown and described herein in what is believed to be the most practicaland preferred embodiments, it is recognized that departures can be madetherefrom within the scope of the invention, which is not to be limitedto the details disclosed herein but is to be accorded the full scope ofthe claims so as to embrace any and all equivalent processes andproducts. All references cited in this application are herebyincorporated by reference herein.

What is claimed is:
 1. A method of processing an item secured in aconnectorless fashion in a push/pull reprocessor, said push/pullreprocessor including a container having a first chamber and a secondchamber and a pressure sensor in each chamber, the method comprising thestep of: generating a flow of a fluid between said first and secondchambers and contacting said item.
 2. The method of claim 1, whereinsaid fluid is an ozonated liquid.
 3. The method of claim 2, wherein saidgenerating step is performed at a pressure or speed such that an amountof time required to kill a given pathogen is lessened for a givenconcentration of ozone in said ozonated liquid.
 4. The method of claim2, wherein fresh ozone is continuously introduced into said ozonatedliquid such that a contaminant in or on said item is continuouslyexposed to said fresh ozone.
 5. The method of claim 1, wherein saidgenerating step comprises configuring a pumping means in said push/pullreprocessor to vary its motor speed in response to said pressure sensorin each chamber.
 6. The method of claim 1, wherein said generating stepis performed at approximately 1-29 psi.
 7. The method of claim 1,further including securing said item in a baffle plug that generates aflow between the item being held and an opening of the baffle plug,thereby creating a turbulent flow to clean the item exterior.
 8. Amethod of processing a lumened instrument secured in a connectorlessfashion in a push/pull reprocessor, said push/pull reprocessor includinga container having a first chamber and a second chamber and a pressuresensor in each chamber, the method comprising the step of: generating aflow of a liquid back-and-forth through a lumen of said lumenedinstrument.
 9. The method of claim 8, wherein said liquid is an ozonatedliquid.
 10. The method of claim 9, wherein said generating step isperformed at a pressure or speed such that an amount of time required tokill a given pathogen is lessened for a given concentration of ozone insaid ozonated liquid.
 11. The method of claim 9, wherein fresh ozone iscontinuously introduced into said ozonated liquid such that acontaminant in said lumen is continuously exposed to said fresh ozone.12. The method of claim 8, wherein said generating step comprisesconfiguring a pumping means in said push/pull reprocessor to vary itsmotor speed in response to said pressure sensor in each chamber.
 13. Themethod of claim 8, wherein said flow exceeds the total internal volumeof said lumen by at least 1%.
 14. The method of claim 8, wherein saidgenerating step is performed at approximately 1-29 psi.
 15. The methodof claim 8, further including securing said lumened instrument in abaffle plug that generates a flow between the lumened instrument beingheld and an opening of the baffle plug, thereby creating a turbulentflow to clean the lumened instrument exterior.
 16. A method ofpreventing or reducing biofilm in an empty push/pull reprocessor, saidpush/pull reprocessor including a container having a first chamber and asecond chamber and a pressure sensor in each chamber, the methodcomprising the step of: generating a flow of a sanitizing liquid betweensaid first and second chambers.
 17. The method of claim 16, wherein saidsanitizing liquid is an ozonated liquid.
 18. The method of claim 17,wherein said generating step is performed at a pressure or speed suchthat an amount of time required to prevent biofilm formation is lessenedfor a given concentration of ozone in said ozonated liquid versussoaking.
 19. The method of claim 17, wherein fresh ozone is continuouslyintroduced into said ozonated liquid such that said chambers arecontinuously exposed to said fresh ozone.
 20. The method of claim 16,wherein said generating step comprises configuring a pumping means insaid push/pull reprocessor to vary its motor speed in response to saidpressure sensor in each chamber.